A Brief Introduction to Chord Theory

You find chords everywhere.

Not just chords but the theory chords represent: Harmony.

A concept of layered sounds separated by specific distances known as ‘intervals’.

What is a scale?

As far as you need to be concerned, a scale is a starting point known as a root followed by notes located at specific intervals. Here is the Major Scale.

To observe the typical ‘do re mi’ major scale that you have most likely been exposed to, play all eight notes of the scale from the root until the octave. Each fret is the same distance apart from those preceding and following.

We call this distance a ‘Semitone’. Therefore the distance between two frets is known as a ‘Tone’. Between the Root and 2nd note of the Major Scale there lies a Tone.

A Tone

This numeric naming process is present throughout each ‘degree’ of the scale. Since this particular scale is the Major scale, they are occasionally prefaced with the word ‘major’ when it is important to make the distinction.

Play the Root and 2nd note of this, the C major scale. You will be alternating between the notes C and D. You are playing a major 2nd interval.

Where do chords fit in?

An appropriate question to ask at this point, knowing that this post is supposed to address a player’s first introduction to chord theory. The answer is that chords take place over specific intervals in the scales from which they are derived. 

This table is a handy tool which highlights the individual distance between each note in the major scale. The scale consists of the following intervals:

Tone,      Tone, Semitone, Tone,       Tone,     Tone, Semitone.

Each note in the scale can be the basis for a chord. The degree of the scale on which you're basing the chord will affect the tonality of the chord. At this point in your learning (~<6 months), Major or minor are the only real tonalities of a chord that you should be concerned with.

By this point you can probably play some songs that you have learned from chords or tab and can maybe work a few things out by ear. Now let’s take a look at building chords in the C Major scale.

C Major:

To build the first chord in the scale, simply take the first note, the third and the fifth from the scale. In this case the notes are C, E and G and the chord is C Major.

But how do we know it’s major (other than being aware of the name of the scale)?

Well, the distance between C, the 1st note and E, the 3rd is two Tones.

Two tones distance is a Major 3rd interval and is the first interval of a Major Triad (Also known as Major Chord).

The distance between the third and fifth in a major chord is one Tone and one semitone.

The second chord in C Major begins from the note D. It follows the same pattern as the first chord only this time, counts from and uses D as the root. This chord has the notes D, F and A.

The distance between D and F is a Tone and a Semitone, that’s a minor third and this is a minor chord.

The distance between F and A, the 3rd and 5th of this chord is two Tones.

See how the intervals are reversed for Major and minor?

As an exercise, try to work through the entire scale, when you get to B, start again at C and continue throughout the next Octave. This will allow you to work out any three note chord which is either minor or Major one of them however is different but which one and why?